 | John Mitchell (F.C.S.) - 1846 - 448 páginas
...Tin gives a grey slag. Zinc leaves a yellowish ring on the cupel, producing a very luminous flame, and occasioning losses by carrying in its vapour silver,...silver. copper alloyed. necessary. to copper. 1000 0 950 50 3 60 to 1 900 100 7 70 . . 1 ASSAY OF SILVER ORES. Standard of silver. 700 600 500 400 300 200... | |
 | John Mitchell (analytical chemist.) - 1854 - 608 páginas
...which the silver undergoes increases with the length of the operation and with the mass of the oxidised matters, it is indispensable to reduce this loss as...following results by the most accurate experiments : — It is remarkable that below the standard of 500, the same proportion of lead must be employed,... | |
 | John Mitchell (F.C.S.) - 1868 - 840 páginas
...which the silver undergoes increases with the length of the operation and with the mass of the oxidised matters, it is indispensable to reduce this loss as...following results by the most accurate experiments : — It is remarkable that below the standard of 500, the same proportion of lead must be employed,... | |
 | John Mitchell (F.C.S.) - 1868 - 808 páginas
...which the silver undergoes increases with the length of the operation and with the mass of the oxidised matters, it is indispensable to reduce this loss as...following results by the most accurate experiments : — It is remarkable that below the standard of 500, the same proportion of lead must be employed,... | |
 | Walter Lee Brown - 1889 - 510 páginas
...some of the base metals. If a large amount of copper is in the bullion, the lead must be increased. "Long experience has proved that silver opposes the...in proportion to the quantity of silver present." (Mitchell.) In cupelling bullion say from 980 to 1,000 fine, 30 grains (about 2 grammes) of lead are... | |
 | Walter Lee Brown - 1889 - 1144 páginas
...copper is in the bullion, the lead must be increased. "Long experience has proved that silver opppses the oxidation of copper by its affinity, so that it is necessary to add a larger imount of lead in proportion to the quantity }f silver present." (Mitchell.) In cupelling bullion say-... | |
 | John Mitchell (F.C.S.) - 1888 - 1002 páginas
...which the silver undergoes increases with the length of the operation and with the mass of the oxidised matters, it is indispensable to reduce this loss as...present. M. D'Arcet has obtained the following results by accurate experiments : — It is remarkable that below the standard of 500, the same proportion of... | |
 | Walter Lee Brown - 1892 - 558 páginas
...some of the base metals. If a large amount of copper is in the bullion, the lead must be increased. " Long experience has proved that silver opposes the...in proportion to the quantity of silver present." (Mitchell.) In cupelling bullion say from 980 to 1,000 fine, 30 grains (about 2 grammes) of lead are... | |
 | Richard Walley Lodge - 1904 - 322 páginas
...Mitchell's Assaying (page 628) is found the following table in regard to an alloy of silver and copper: " Long experience has proved that silver opposes the...in proportion to the quantity of silver present." Sufficient lead must be added to cause the button to unite well. If too great an excess is used, however,... | |
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... matters, it is indispensable to reduce this loss as much as possible by reducing the proportion of lead to that which is strictly necessary. Long experience has proved that silver opposes the oxidation of copper by its affinity, so that it is necessary... 